"What do you want to be when you grow up?" Rings in my ears like the scream from 125cc, five cylinder Honda RC149. After combined Wimbledon & Formula 1 World Champion was laughed out of court I settled on motocross race engineer, although that required being able to count and hand homework in on time so it was back to the drawing board, rather than the draughtmans board. Thankfully, Alexandre & Osvaldo from It roCkS!bikes in Portugal managed to avoid the coursework munching dog and both qualified as proper engineers. That was a while ago now though and the two experienced masters of metal have been imparting their innovative and calculating methods on motorcycles under their own banner from a modest facility in Oporto. Their niche is the monocoque. A tried and tested method for many decades in four-wheeled motorsport and trialled on occasion on motorcycles but the single piece fuel tank and seat unit hasn't ever caught on, until now. OK, so perhaps more unibody than monocoque but the latter sounds way better. The guys turned up to Bike Shed London with not one but two bikes from the Yamaha Yard Built series. Producing one bike for Shun Miyazawa and his team is no easy feat, but two, that's high praise indeed. They also had to satisfy the project sponsors, Yamaha Portugal and national motorcycle magazine Motociclismo. This SR400 CS_05 Zen sat alongside the XJR1300 Dissident and more than held its own against a bike that has had tongues wagging all summer. Up close the Zen simply makes you smile. With plenty of other awesome kit around during the exhibition there were a handful that had the just give me the keys factor, this little SR has that in spades. I threw a leg over the thing and imagined a few corners at Rossi's Ranch, it simply feels fun, and that's with the engine switched off. A brand new SR400 straight of the production line was given over to the project. A successful re-release under Yamaha's Sport Heritage sub-brand, the new version of this iconic midsize single now features bureaucrat friendly fuel injection but apart from a couple of tweaks here and there the donor is essentially the same bike that left the Iwata factory 30 years ago. And why not, the original design emphasised the easy to use philosophy and was a huge global hit. Speaking of universal popularity, here's a photo of Motogadget's accomplished turn signal solution, the M-Blaze. There's a Motoscope mini too. Engineered by fastidious Germans and available to the masses, eradicating the need for protruding and cumbersome indicators fore and aft. But you're probably not looking at this bike and wondering about amber-flashing legalities. The bodywork isn't just slapped on, covering the old frame. Considerable forethought and fabrication has been combined to create a tubular steel platform upon which the new clothes hang, held in place by a minimal number of fasteners allowing for a few twists of ratchet to remove the entire unit. The exquisitely upholstered seat leather pad is ergonomically perfect, allowing the rider to easily slide forward, right up onto the tank, just incase the flat track beckons. The other obvious alteration is the suspension set-up. Gone are the traditional twin shocks, superseded by a cantilever monoshock, a short one too at 240mm, sporting just 36mm of linear travel. The mesh-braced swingarm maintains the original arc of movement and overall suspension travel but leaves the rear end visually clear, and centralises mass and all that snazzy engineery stuff. The Jekyll and Hyde paint job looks great up close and offers a pleasant change from the teutonic monochrome palettes that have graced customs of late. Although this scheme was driven by the need to deliver association with the sponsoring corporate partners. I like the red side the best, unless I'm looking at the right hand side, than that's favourite. A great view from this high fence. The tracker-style mesh number board is super simple yet effective, with a single projector headlamp more than sufficient for nocturnal activities. Knobbly tyres are a frequently criticised addition to some builds, but here, anything less than the Bridgestone 'crosser rubber fitted would leave one yearning further off-road cues. With the overall aesthetic dialled in, an aural upgrade was needed to match. The in-house fabricated stainless exhaust adds a few more decibels and releases a pony or two from the otherwise stock motor. Well, the open filter should help the 399cc single breath a bit better too whilst adding intake roar to the soundtrack. The proportions are spot on, the stance is squat and racy without being slammed and awkward. Frankly, if Yamaha were able to put this into production they'd be a queue at the local dealership. But that's just it, Yamaha can't do such a thing because accountants, red tape technicians and the fun police wouldn't allow it. Which is the whole point of the Yard Built Series, allow free-thinking and creative engineers to produce replicable components and performance parts so that the everyman can join the custom party at their own pace. The Dissident kits are available for the XJR1300 so we presume this simple to fit package for the SR will be available at some point. The guys from it roCkS!bikes might have made the most dyslexically challenging brand name in recent times but they more than make up for it with ingenuity and meticulous craftsmanship. We hope to see more of their bikes on these pages before too long and perhaps an SR400 similar to this gracing Bike Shed London at some point. For more on it roCkS!bikes head to Bike Shed Archive | Facebook | Web | Instagram